07 August 2019

LEGO® Ideas set review: 21318 Treehouse

Posted by Admin
Time for the second part of our LEGO® Ideas 21318 Treehouse review, looking at the build. We covered its elements in part 1.

In a great alteration to Kevin Freeser's original fan submission, which had a grey square base, César Soares' official version has an irregular green shape with a stream running through it. The stream is Dark Azure plate (including the 4x8, Element ID 6209672, its third appearance in sets) with a layer of Transparent 1x1 and 1x2 plates on top.

New Transparent

This is actually the first set I’ve built containing the new transparent formula. We’ve not yet discussed this here on New Elementary but it was spotted a few months ago by many people. The LEGO Group (TLG) have changed the plastic used to make some - perhaps all - transparent colours. We know it used to be polycarbonate (PC) but we don’t know what the new one is; TLG are naturally cagey about revealing anything that might help their competitors or imitators.

If you’ve ever put a load of transparent pieces together your fingers will have informed your brain that PC is harder and sharper than regular ABS pieces. These new ones hurt less; while not soft, the new plastic is softer to the touch than before. The new Transparent seems slightly yellower, slightly foggy and the surface is less glassy. By making a cube five plates thick of old and new Transparent 1x2 plates, I could easily see the difference (although I wonder if I would have noticed had I not already know? Click/tap image to enlarge these photographs, let us know your thoughts in the comments). Certainly when applying a single layer of them on top of coloured pieces, as is done in this model, the difference is in no way apparent.

Our friend Jang of Jangbricks reports that he has noticed the change in the following colours:
  • Transparent [TLG]/ Trans-Clear [BL]
  • Transparent Light Blue/ Trans-Light Blue
  • Transparent Blue/ Trans-Dark Blue
  • Transparent Bright Orange/Trans-Orange
  • Transparent Brown/ Trans-Black
  • Transparent Bright Green/ Trans-Bright Green

He hasn't yet seen it in Transparent Yellow, Red or Green and the fluorescents are difficult to judge but presumably they'll change too. Any of you noticed it in those? Jang also feels the sound of the new transparent has less "ring" to it.

The situation can of course be used to your advantage if you keep your new Transparent parts separate and reserve them for situations where a slightly foggier, yellower effect is what you desire. Many have mentioned they find the change to Transparent Light Blue noticeable and that they intend to exploit this in models featuring water. But it’s a hassle to separate them, for minimal reward.

People who like putting LEGO under black light will definitely be keeping them separate though. UV makes certain colours/formulations glow; the old formula did not glow but the new one does, as this video by BricksAhoy clearly demonstrates.

So while sorting the two types will be a pain for people creating UV displays (remember also, they can’t purposefully buy batches of only one or the other from BrickLink) there’s the bonus for them of the fact that there are now glowing transparent pieces that they can use in their creations.

So: will the majority of LEGO customers notice the change, or care? No. Will the majority of AFOLs? I suspect so! But whether you are for or against or don't care, do let us know your feelings in the comments. Personally, I’m a massive fan of Transparent; it’s "my precious" LEGO colour, and I certainly do not like this change. In my view, Transparent should alter the colour beneath it as little as possible. And a foggy Transparent is, by definition, less transparent.

The issue has been raised on the LEGO Ambassador Network but while acknowledging there's been a change, TLG have not revealed how or why. Maybe the sharper edges were becoming considered to be a safety issue? It surely can't be a materials change to plastic from a sustainable source as they'd be shouting this from the rooftops, or treetops in this case. But frankly, they’re under zero obligation to tell us such things. While TLG are always mindful of the “bley rebellion” of angry AFOLs after they changed some colours in 2004, there are limits to how much they will reveal about their work to us fans.

Ultimately, while I am upset by the change, I know it's not the end of the LEGO world and I just have to ‘suck it up’. I actually think there will be an increasing number of undesirable changes we AFOLs will have to suck up in the coming years, as TLG move to sustainable sources for plastic production which will inevitably force some compromises upon the way LEGO elements look, feel, sound and behave.

[EDIT: Since publishing this article, my New E colleague Francesco Spreafico has made me aware that many European countries may be intending to ban or restrict the use of PC from consumer products for environmental and health reasons. This sounds like an extremely likely reason for this change, however there is no such official statement from The LEGO Group on this.]

Hang on, I was meant to be discussing a treehouse. Enough of my transpa-rant.

Trunk techniques

The aforementioned base is constructed from a Technic frame sandwiched within layers of plate. A single Technic beam rises vertically to attach the trunk. It puzzled me that, in order to secure the red 2x2 plates with 2 studs, the 1x4 tiles are placed over the stud-free area of the red plates. I wonder if they found they needed a little lee-way to allow for movement of the trunk in the finished model, i.e. maybe the red piece was originally regular plate but was under too much stress when secured completely? Anyone have any other ideas?

I anticipated the trunk being Technic as well, for strength, but its core is instead constructed of System parts including large door frames, all cross-braced using sideways building.

One side is red for orientation; an important aspect throughout the instructions given the constant likelihood of attaching things to the wrong side. The outward-facing bricks are used to attach the larger sides of the tree.

You can also see in the picture above that Black 'Minecraft feet', Plate 1X2 W/ Vert. Tube
(Element ID 6250020| Design ID 41682), are used to attach the trunk to the base, although of course an axle is also threaded through the Technic beam.

Note too, the Black ‘espresso plates’, Plate 1X1 Round W/ Horizontal 3.2 Shaft (6196548|32828), along each of the four corner edges with their 3.18mm bars protruding.

They are included to attach four narrower plates at 45° via blue Technic half-pins, to create an octagon.

This technique continues upward, interrupted by the three strong branches that support the three cabins. Two of these branches project at the usual 90° angles but the other is off-grid; strongly supported by what seems a bizarre layer of seemingly random rounded parts until you connect the branch and it all makes sense.

As the trunk narrows, a more traditional 'Lowell Sphere' style of technique is employed instead but with the core interrupted by connections for the upper branches that will contain leaves, including some at 45°. To accommodate these protrusions, the plates applied sideways form an interesting bottle-like shape.

The build process is pleasing and not strictly repetitive – within the main trunk, there is literally only one instance of the dreaded "2x" callout warning you that you'll need to create a sub-build twice. Everything else is unique, although there are many similarities in each sub-build, which is comforting but doesn't allow you to switch your brain off because small differences in decoration and construction are always appearing.

Reading the instructions is a little harder than usual because of the sheer amount of Reddish Brown on Reddish Brown. Outlining new parts in each step might have helped, or at least having the Dark Brown elements outlined in white. I'm sure it will be fine for most people – I only notice this stuff nowadays as my eyesight is getting a lot worse!


The cabins are octagonal, slightly wider along one dimension. It's nice to see the weird Plate (A) 4M 45° (Design ID 15706) used, to create the 1-module wide balcony on the angled sides.

It is now that the level of detail injected into this set truly becomes apparent. Here is the parents' bedroom under construction.

I particularly appreciated the logical thought that went into the plumbing in the bathroom, with an external water tank feeding a detailed shower, basin and the obligatory LEGO toilet – this time constructed of wood. Even the roll of toilet paper looks eco-friendly!

The roofs are a geometric joy that use ball/cup joints for the four corners and, for the elongated centre, Plate 2X3 W/ Hor. 3,2 Shaft in Dark Red (6220561|30166) which fits oh-so-snugly.

It's a shame Dark Red was chosen (when it seems that Dark Stone Grey is available) as it is visible through the gaps. There are a lot of gaps throughout this model and they really don't bother me, apart from this one.

The instructions don't dictate a "correct way" of angling the four corner pieces which is nice as you can decide how you want the roofs to look. However I felt there was a correct way, where the 2x3 Reddish Brown plates underneath hug the central plates neatly.

Just when I thought it was getting dull because the first two roofs are identical in structure bar their decoration, the third roof surprises with the elongated edge running at right angles to the cabin below. Another nice wake-up!

As mentioned in our exclusive interview with César Soares, the lanterns attached to the cabins are noteworthy for being brick-built and including Mini Hat No 16 in Black (6138812|25264), only previously used in various minifigures from the Black Panther theme, and the Oni Villain from Ninjago. You get three plus one spare in the Treehouse.

The level of detail extends to providing a method for the inhabitants to move from cabin to cabin, and the rope stairs make impressive use of rounded parts to allow you flexibility in how the steps are angled.

They are connected firmly and look great, although you need to ensure the end near the door is well pressed down to allow the door to open.

The stairs leading up to the cabins are another feast of neat geometry and organic shapes.

With the trunk and cabins complete, the final three numbered bags plus five of the unnumbered bags will be used to create the treetop.


The three layers of branches are basic, decorated oblongs connected by click hinges with leaves attached securely. This is the only part of the build that approaches dull repetition, as although there is variance, it is deliberately kept minimal. Tempting as it might have been to create more complex and unique branch shapes, this would have proved frustrating later when you remove the branches to change all the leaves to the autumn colour. With each level of branches pretty much the same, you then don't need to worry about replacing the right branch in the right place again. Also, the model doesn't really need complex branch shapes; the finished effect is extremely organic thanks to the leaves and the ability to angle the branches. 

The whole treetop lifts off the top of the trunk via an axle, with coloured parts in the core making it easy to align when reattaching. Chainsaw not included.

The roofs also come off easily as they just rest on their supports, again with colour-coding provided to easily put the right roof back on the right cabin.

Completing the model

You can view the finished model from any angle – there's no specific front side – and there is plenty to play with, and to photograph!

The three rooms are the parents' bedroom, the kids' bedroom and the bathroom – with no kitchen cabin, the residents cook on an open fire made of Harry Potter wands and feast at a table.

Snacks and other supplies can be winched up to the cabins.

Relax by the stream or enjoy a gentle swing.

At night the sky is your plaything. I love that the telescope viewfinder is correctly placed on the side rather than looking through the end.

Of course, the completed model is not fully complete until you've changed all the leaves to the supplied autumnal colours. Note here also that I went for an asymmetrical arrangement with the branches to reveal more of one of the roofs. It's really fun arranging the branches plus the strings of leaves to suit your photographs, or to make the model look its best according to the height of your display shelf.

The branches can actually be moved a lot more than you might expect!
That means this model could claim to being over 50cm high... if you want it to look like a broccoli bush, that is.


Having built this set I really want to shoot myself… with a shrink ray, so I can crawl inside it and live there forever. It begs to be played with and for grand stories to be told. The attention to detail, 360° play access and strength make it a charming and imaginative model. Adding green grass, nougat walls and dark blue roofs into the colour scheme is an improvement on Kevin's version I feel, creating contrast and making the model appear more dynamic.

From the "New E perspective" there's the thrill of the 55 leaves in Flame Yellowish Orange [TLG]/ Bright Light Yellow [BL] (Element ID 6273388) and the cute carved inscription on Plate W. Bow 2X2X2/3 (6283550), but that's it for new stuff. And much as we love a new colour for an existing part, I'm frankly impressed César managed this huge build only requiring one part to be recoloured. Ultimately the most exciting aspect parts-wise is the quantities, which I ran through in part one. These are 3,036 pieces you'll be happy to add to your collection, unless you hate brown.

There are interesting techniques in the trunk section and gorgeous details in the cabins section. Building the treetop section is unremarkable. Changing the leaves is easy enough, and a nice mindless task. There are lots of gaps in the model, which doesn't trouble me (apart from the aforementioned dark red pieces visible inside the roofs) as they add to the organic rustic look, but may trouble others more.

21318 Treehouse is available now priced £179.99 / $199.99 / 199.99€.

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  1. I will not excuse your transpa-rant. Puns like that are a pane. Clearly.

  2. Trans-clear has long been a problem, but most people haven't really noticed. Just in polycarbonate, it came in three distinct shades: clear, yellowish, and bluish. Spencer Rezkalla, of miniscale fame, has lamented this on several occasions (usually when he gets a batch of the yellowed clear from LUGBulk). I've had to carefully sort clear parts for when I'm building cars so I don't end up with tiger-striped headlights on modern body styles. If they can start being consistent, I actually wouldn't mind having a permanent tint like this.

    Also, the UV thing will probably be _very_ welcome, especially as I know someone who is really upset after finding out that Trans-Medium Blue (Trans-Fluorescent Blue) has been culled from the production color list.

    1. True, I did intend to mention this is far from the first change to Transparent and pull out some examples, but I was going on a bit as it was! - suffice to say, this is a more significant change imho

  3. Is there any change in the clutch power of the new transparent parts? It was sometimes something of an issue that PC on PC created a comparatively huge amount of friction, most notably in that a 1x1 cone on a 3.18 shaft is basically impossible to remove if both are transparent.

  4. I just examined the trans-purple, trans-dark pink and transparent bricks in 70825 Queen Watevra's Build Whatever Box!, and compared them to the trans-dark pink bricks in 10703 Creative Builder Box from 2017, and I can confirm that trans-purple and trans-dark pink are also being made with the new material. In particular the new trans-dark pink is noticeably more opaque and less refractive. I'll try to provide comparison photos once I finally get around to reviewing the set on my site.

  5. As written above, it may indeed have to do with the fact that (as forbidden in Lego's "rulebook") PC parts inside other PC parts are too hard to remove for kids.
    That, or they wanna look more like Lepin, since foggy trans clear was typical of clone brands?
    For a second I thought this was an article on new 1x2 rounded plates in trans clear, sadly not..

    Btw this reminds me of the 44676 trans clear flag that was, in some SW battlepack (75166), randomly clear or frosted. But it probably had to do with the molds of 44676 that have different textures, some shiny some not. Still, funny that some people got an obviously frosted one.

    1. Too hard for kids? I've snapped off 4L bars when trying to remove them from cones! I mean, there was a point where they just had to accept that they had an unanticipated engineering snafu on their hands. Word is the 4L and 3L bars ended up being made out of a different material than polycarbonate (can't remember if it was ABS, or something entirely different), specifically because they couldn't prevent consumers from shoving them into cones.

  6. I have just edited the article with an interesting update: Since publishing this article, my New E colleague Francesco Spreafico has made me aware that many European countries may be intending to ban or restrict the use of PC from consumer products for environmental and health reasons. This sounds like an extremely likely reason for this change, however there is no such official statement from The LEGO Group on this.

    1. But isn't the article only talking about food-related products? It's about banning bisphenol A that's a long-term health risk in baby bottles - I can't imagine kids licking their Legos enough for a ban to be imaginable.

      That's for the health reasons. As for the environmental ones, there are plans to ban quite some stuff, like cotton buds & plastic straws very soon, but that's because they end up in trash, pollute seas & fill bird & tortoise guts. While Lego sometimes end up in the sea, I just can't imagine a related ban on Lego here, plus it's not related to PC, but all plastics (or anything that last nearly forever).

  7. Looks like the continue reading break is missing so the whole article is displayed on the front page.

  8. Nice Article! I suggest maybe you look at the 40 tooth gear, and how it appears in a few odd colors in some clock sets from 2000-2002.

  9. Just started building 70423 Paranormal Intercept Bus 3000 and all transparent parts in this set are of that new material. It actually feels a bit polypropylenish.

  10. https://1.bp.blogspot.com/-2NtO1CLAZX0/XUlTWId6X-I/AAAAAAAALqs/FjWfoeYEMbUtbR7iu50c_8AzsbXYpoXuQCEwYBhgL/s640/04-technique-upper-trunk.jpg
    "The build process is pleasing and not strictly repetitive – within the main trunk, there is literally only one instance of the dreaded "2x" callout warning you that you'll need to create a sub-build twice. Everything else is unique, although there are many similarities in each sub-build, which is comforting but doesn't allow you to switch your brain off because small differences in decoration and construction are always appearing."
    ^The Above section is my literal deterrent right now. That bottle shaped section with the x cross ring through it is preventing me from finishing this as a gift build for a parent. I was frustrated enough I put it aside and sought out help, even going so far as to message lego themselves asking if there's been a revised bag 14 for the kit.

    The third image if the pegs connect they inevitably break the cap of the 'bottle' shape.